Meanwhile, Mount Pleasant and Marina South stations, which were structurally completed as part of Stage 3, remains non-operational due to the perceived lack of developments in the area at this given time.

In January 2019, an infill station known as Founders' Memorial was announced to complement its namesake, with the LTA additionally considering to integrate the Changi Airport Branch that is currently a part of the East West Line (EWL) into the TEL.

When fully opened, it is expected to serve about 500,000 commuters daily in the initial years before rising to one million in the long-term.

[5] New and improved signage was introduced to alI stations along the TEL, which saw less text and wordiness in place of more illustrations and visualisations.

Several architectural and engineering consultancy packages were released in 2010 which indicated an increase in the number of stations from 18 in the initial announcement to the current 22 and length of the line from 27 to 30 km (17 to 19 mi).

[7] On 16 June 2011, LTA announced the location of the depot for the line, which was due to begin construction at the end of 2012.

It also announced Woodlands as an interchange with the existing North South Line and an additional station located near to Republic Polytechnic.

[12] In its preliminary plans, ERL was to have been a 40 kilometre rectangular loop that would complement the existing East West line and enhance inter- and intra-town travelling in the eastern region.

On 11 July 2012, Josephine Teo, Minister of State, Ministry of Finance and Ministry of Transport, announced that the Land Transport Authority is starting architectural and engineering consultancy studies for the Eastern Region Line, which will eventually connect to the Thomson Line.

[14] The director of rail services from LTA, Melvyn Thong, said on 29 May 2013 at the Modern Railways conference that there are plans to extend the Eastern Region Line to the future Changi Airport Terminal 4 which was at that time, set to be ready by 2017[15] but on 1 June that year, the Land Transport Authority clarified that the Eastern Region Line will not provide an MRT link to the planned Terminal 4.

[21] On 28 August 2019, the Land Transport Authority awarded several non-fare businesses along the line, with Asiaray Connect awarded an advertising contract and a consortium, made up of SMRT Experience, JR Business Development SEA and Alphaplus Investments appointed to run retail space.

[22] On 19 September 2019, Transport Minister Khaw Boon Wan revealed that the opening of the first stage of the Thomson–East Coast Line from Woodlands North to Woodlands South stations was delayed to January 2020 from the indicative time of 2019 announced earlier,[23] subsequently confirmed as 31 January 2020.

[35] On 17 August 2022, LTA handed over Stage 3 stations along the line to SMRT to get the section ready for operations by the end of 2022.

[36][37] On 7 October 2022, during a visit to the Outram Park and Maxwell TEL stations, Transport Minister S. Iswaran announced that the third stage of the line will commence operations on 13 November 2022.

[41] Acting Minister for Transport Chee Hong Tat said in an interview with Lianhe Zaobao that the authorities hope to open the sector in the first half of that year.

[54] It continues heading south-east, bypassing Ang Mo Kio, towards Lentor before curving south towards Mayflower station.

[40] It then enters the Downtown Core, by heading in a south-east direction towards Marina Bay station, which has an interchange with the North-South and Circle lines.